Cancer metastasis on chip

Most breast cancer related deaths are not caused directly by the primary tumor, but by secondary tumors formed through metastasis to other organs [1]. Current in-vitro models rarely mimic the initial phase of metastasis: invasion. Hence, we focus on modeling breast cancer invasion and the relevant microenvironment on a chip. We develop microfluidic Cancer-on-a-Chip (CoC) devices to recapitulate essential cues in cancer microenvironment, namely (1) Extracellular Matrix (ECM) heterogeneity and (2) microvasculature. To generate the cancer niche, we use cell-embedded hydrogel encapsulation [2]. A water in oil flow-focusing device was used to encapsulate cancer cells in Matrigel beads. Next, Matrigel beads were cultured in collagen I hydrogel, mimicking the stromal ECM. This way we recapitulate the pre-invasive condition where cancer cells initially reside in a soft basement membrane before invading the fibrous and stiffer stromal ECM. Beside encapsulation method, we use alternative techniques like sugar-printing in CoC models to create the interface between two different materials. The model of ECM heterogeneity can potentially lead to better understanding of pre-invasive and invasive breast cancer.Moreover, we use sugar-printing technology to create perfusion lumens, cast directly in ECM [3]. When seeded with endothelial cells, these form the (micro) vasculature. Combined with a neighboring channel for cancer cell culture, the process of cancer invasion, migration through ECM, and intravasation can be studied. This way we avoid using artificial materials like Polydimethylsiloxane (PDMS) which usually have drawbacks for cellular experiments.<br/

A model for the impact of the nanostructure size on its gas sensing properties

The size of a metal oxide nanostructure plays a key role in its performance as a gas sensor.</p

An in vitro model of cancer invasion with heterogeneous ECM created with droplet microfluidics

Metastasis is a multi-step process that is critically affected by cues from the tumor micro-environment (TME), such as from the extracellular matrix (ECM). The role of the ECM in the onset of metastasis, invasion, is not yet fully understood. A further complicating factor is that the ECM in the TME is mostly heterogeneous, in particular presenting a basement membrane (BM) directly enveloping the tumor, which acts as a barrier to invasion into the surrounding stromal ECM. To systematically investigate the role of ECM in invasion, appropriate in vitro models with control over such ECM heterogeneity are essential. We present a novel high-throughput microfluidic approach to build such a model, which enables to capture the invasion of cancer cells from the tumor, through the BM and into the stromal tissue. We used a droplet-maker device to encapsulate cells in beads of a primary hydrogel mimicking BM, Matrigel, which were then embedded in a secondary hydrogel mimicking stromal ECM, collagen I. Our technology ultimately provides control over parameters such as tissue size, cell count and type, and ECM composition and stiffness. As a proof-of-principle, we carried out a comparative study with two breast cancer cell types, and we observed typical behavior consistent with previous studies. Highly invasive MDA-MB-231 cells showed single cell invasion behavior, whereas poorly invasive MCF-7 cells physically penetrated the surrounding matrix collectively. A comparative analysis conducted between our heterogeneous model and previous models employing a single type of hydrogel, either collagen I or Matrigel, has unveiled a substantial difference in terms of cancer cell invasion distance. Our in vitro model resembles an in vivo heterogeneous cancer microenvironment and can potentially be used for high throughput studies of cancer invasion.</p

Thermal And Mechanical Behaviour Of Recycled Polypropylene/Polyethylene Blends Of Rejected-Unused Disposable Diapers

This paper presents the characterization of recycled plastic that derived from the rejected-unused disposable diapers containing polypropylene (PP) and polyethylene (PE), noted as r-PP/PE. The blends were tested for thermal, mechanical and morphological properties. Tensile test showed that the r-PP/PE is lower in strength and strain but higher for modulus in comparison to the v-PP/PE by 56%, 55%, and 2% respectively. For the flexural properties, the r-PP/PE also has lower in strength, strain, and modulus as 67%, 13%, and 77% respectively. Lower absorbed energy and impact strength was observed in r-PP/PE, 36% and 24% respectively compared to v-PP/PE. Thermal analysis revealed that the degree of crystallinity of recycled PP and PE was 19% and 20% lower than the virgin possibly due to thermal degradation during the process. Morphological examination revealed the present of impurity, phase separations and inhomogeneity were found in the r-PP/PE as compared to v-PP/PE that might contribute to their lower strength

Modeling leaf production and senescence in chickpea

Quantitative information regarding leaf area development in chickpea (Cicer arietinum L.) is scarce. Data from four field experiments with a range of treatments including genotype, sowing date and plant density across 4 location-season combinations were analyzed to quantify main effects of temperature, photoperiod and plant population density on plant leaf area in chickpea. All experiments were conducted under well-watered conditions. Maximum rate of main stem node development was 0.72 nodes d-1. Cardinal temperatures for node appearance were found as 6.0, 22.2 and 31.0 oC for base, optimum and ceiling temperatures, respectively. Plant density had no effect on cardinal temperatures for leaf appearance and phyllochron. Leaf senescence on the main stem started when the main stem had about 12 nodes and proceeded at a rate of 1.67% per each day increase in physiological day (a day with non-limiting temperature and photoperiod). Leaf production per plant versus main stem node number occurred in two phases; phase 1 when plant leaf number increased with a slower and densityindependent rate (3 leaves per node), and phase 2 with a higher and density-dependent rate of leaf production (8- 15 leaves per node). A close relationship was found between the fraction of senesced leaves per plant and the same fraction on the main stem. The average leaf size per plant increased from 4 cm2 when there were 10 nodes on the main stem and stabilized at 10.8 cm2 when there were 21 nodes on the main stem. Plant density and sowing date did not affect leaf size. Plant leaf area was also predictable directly from main stem node number. The relationships found in this study can be used in simulation models of chickpea

Interplay of electrokinetic effects in nonpolar solvents for electronic paper displays

Hypothesis: Electronic paper displays rely on electrokinetic effects in nonpolar solvents to drive the displacement of colloidal particles within a fluidic cell. While Electrophoresis (EP) is a well-established and frequently employed phenomenon, electro-osmosis (EO), which drives fluid flow along charged solid surfaces, has not been studied as extensively. We hypothesize that by exploiting the interplay between these effects, an enhanced particle transport can be achieved. Experiments: In this study, we experimentally investigate the combined effects of EP and EO for colloidal particles in non-polar solvents, driven by an electric field. We use astigmatism micro-particle tracking velocimetry (A-μPTV) to measure the motion of charged particles within model fluidic cells. Using a simple approach that relies on basic fluid flow properties we extract the contributions due to EP and EO, finding that EO contributes significantly to particle transport. The validity of our approach is confirmed by measurements on particles with different magnitudes of charge, and by comparison to numerical simulations. Findings: We find that EO flows can play a dominant role in the transport of particles in electrokinetic display devices. This can be exploited to speed up particle transport, potentially yielding displays with significantly faster switching times

HAKI : Aplikasi Tracer Study STIKOM Surabaya (TRUST)

TRUST adalah aplikasi studi pelacakan jejak lulusan/alumni yang dilakukan kepada alumni Institut Bisnis dan Informatika Stikom Surabaya 2 tahun setelah lulus berbasis web. Aplikasi ini bertujuan untuk membantu bagian pusat karir perguruan tinggi, Stikom Career Center (SCC) dalam menganalisis: (1) outcome pendidikan dalam bentuk transisi dari dunia pendidikan tinggi ke dunia kerja, (2) output pendidikan yaitu penilaian diri terhadap penguasaan dan pemerolehan kompetensi, (3) proses pendidikan berupa evaluasi proses pembelajaran, dan (4) kontribusi pendidikan tinggi terhadap pemerolehan kompetensi, serta (5) input pendidikan berupa penggalian lebih lanjut terhadap informasi sosiobiografis lulusan. Selain digunakan untuk keperluan akreditasi, SCC juga sejak tahun 2016 menggunakan aplikasi TRUST sebagai alat monitoring lulusan Stikom Surabaya dalam memasuki dunia kerja

Phylogenetic Findings Suggest Possible New Habitat and Routes of Infection of Human Eumyctoma

Eumycetoma is a traumatic fungal infection in tropical and subtropical areas that may lead to severe disability. Madurella mycetomatis is one of the prevalent etiologic agents in arid Northeastern Africa. The source of infection has not been clarified. Subcutaneous inoculation from plant thorns has been hypothesized, but attempts to detect the fungus in relevant material have remained unsuccessful. The present study aims to find clues to reveal the natural habitat of Madurella species using a phylogenetic approach, i.e. by comparison of neighboring taxa with known ecology. Four species of Madurella were included in a large data set of species of Chaetomium, Chaetomidium, Thielavia, and Papulaspora (n = 128) using sequences of the universal fungal barcode gene rDNA ITS and the partial LSU gene sequence. Our study demonstrates that Madurella species are nested within the Chaetomiaceae, a family of fungi that mainly inhabit animal dung, enriched soil, and indoor environments. We hypothesize that cattle dung, ubiquitously present in rural East Africa, plays a significant role in the ecology of Madurella. If cow dung is an essential factor in inoculation by Madurella, preventative measures may involve the use of appropriate footwear in addition to restructuring of villages to reduce the frequency of contact with etiologic agents of mycetoma. On the other hand, the Chaetomiaceae possess a hidden clinical potential which needs to be explored

Modeling DNA Structure, Elasticity and Deformations at the Base-pair Level

We present a generic model for DNA at the base-pair level. We use a variant of the Gay-Berne potential to represent the stacking energy between neighboring base-pairs. The sugar-phosphate backbones are taken into account by semi-rigid harmonic springs with a non-zero spring length. The competition of these two interactions and the introduction of a simple geometrical constraint leads to a stacked right-handed B-DNA-like conformation. The mapping of the presented model to the Marko-Siggia and the Stack-of-Plates model enables us to optimize the free model parameters so as to reproduce the experimentally known observables such as persistence lengths, mean and mean squared base-pair step parameters. For the optimized model parameters we measured the critical force where the transition from B- to S-DNA occurs to be approximately $140{pN}$. We observe an overstretched S-DNA conformation with highly inclined bases that partially preserves the stacking of successive base-pairs.Comment: 15 pages, 25 figures. submitted to PR